Parts of "Avatar" have already begun shooting in Los Angeles, though production will move to New Zealand in October to take up residence on the Weta Digital soundstages there.

The plot, which takes place in a galaxy far, far away, involves a battle between humans and some wacky CGI aliens. Cameron has been tweaking the script for around a decade. Lang will play a Marine colonel dispatched to the planet of Pandora to take care of its troops, according to Variety. Rodriguez will play an ex-Marine pilot.

The 20th Century Fox production, budgeted in the $200 million range, has already staked its claim to a May 22, 2009 release date, when it will hit theaters in both digital 3-D and 2-D formats.

In addition to her brief and not-exactly-embraced turn as Ana-Lucia Cortez on "Lost," Rodriguez has also appeared in "Girlfight," "BloodRayne" and the upcoming "Battle in Seattle."

While best known for his Tony nominated theater work, Lang's feature credits include "Gods and Generals" and "Manhunter."